Combine flour, wheat germ, baking soda, salt, baking powder, and walnuts.
Set aside.
In a large bowl, beat eggs with an electric mixer until blended.
Add oil, sugars, and maple flavoring; continue to beat until mixture is thick and foamy.
Add flour mixture and stir just until blended.
Stir in zucchini.
Divide batter equally between 2 greased, flour-dusted 5- by 9-inch loaf pans.
Sprinkle sesame seeds evenly over batter.
Bake in a 350° oven until a slender wooden pick inserted in centers of loaves comes out clean, about 1 hour.
Let cool in pans for 10 minutes; turn out of pans onto racks and let cool completely.
To store, wrap airtight; hold at room temperature for up to 4 days or freeze for up to 1 month.